Uplink is trivial on 2 meters. 5 watts to a whip should do it. BUT uplinks are congestion limited. There is a 22 dB link advantage to a 2m omni antenna uplink compared to the UHF downlink to an omni antenna!!!!
That is why PCSAT used 2m up and down.
So conventrate on HEARING the satellite, the uplink is free, unless you need to step on everyone else to get in. Then the only solution (unfortunately) is "more power than everyone else"...
But with 1 second packets, APRS satelites dont have as much of an issue with congestion.
Bob, WB4APR